Due to the limitation of its production process, the production cost of seamless steel tube has been high, which leads to the gradual decline of its economic benefits. With the development of technology, new products have appeared in China's metallurgical industry, instead of the reduction of hot stretching of seamless steel tubes.


1. Quality directly determines the quality of welded pipe. The biggest difference between ERW and seamless pipe lies in this. Longitudinal high-frequency welding can not eliminate the carbon in the straight seam, but the welding interface and the matrix are not fully integrated, and can not withstand the test of time and pressure. Reducing the overall thermal tension of high frequency welded steel pipe after 800 degrees of heating temperature, overall annealing, and then open conversion treatment, after this series of processes, the weld and matrix structure have the same performance, fully integrated into one, from seam to seamless transition are well done.


2. As a result of the difference of product quality between different processes, the thermal stress in high frequency welded pipes was reduced by longitudinal processing, and the burrs inside and outside were removed off-line. Burr's presence can affect the flow of fluid in the pipeline, blocking the normally flowing Neptune casino and causing the whirlpool. According to the principle of fluid mechanics, the unavoidable increase of partial pressure and discontinuity of welding greatly reduce the safety factor of pipeline. The risk of burr is fully considered in the production process of hot drawing reduction steel, and the removal of burr is limited, so that the thickness is uniform, the appearance and seamless difference are not found. So from this point of view, the seamless transition of the hot-stretched vacuum pipe joint has been completed.


On the basis of longitudinal decompression heat pipe, on-line deburring, integral heating variable and a series of new processing technology are carried out, which make it get a qualitative leap under high pressure and can be widely used in this field. Longitudinal is limited to water and low pressure gas transmission environment.